At present, although mobile phones of the same model which are produced by a mobile phone vendor use the same components, parameters of the components still have tiny differences, and data preconfigured in the mobile phones by the mobile phone vendor is not precise enough, so that the mobile phones manufactured through different parameter combinations consequentially have differences. Before formally starting to use a mobile phone, correspondence between a transmit signal and an input voltage of a power amplifier shall be detected to retrieve correspondence between transmit power of the transmit signal and the input voltage. Therefore, the input voltage may be precisely adjusted, so as to make the transmit power of the power amplifier meet a requirement of the transmit signal.
The power amplifier generally has multiple power levels, correspondence between transmit power and an input voltage under each power level is individually a different linear relationship with others, and a method for detecting the correspondence between the transmit power and the input voltage of the power amplifier under each power level is as follows: A pair value (P, Vacp) of transmit power and an input voltage within a range of one power level is detected, and according to the correspondence between the transmit power and the input voltage, a curve of the linear relationship between the transmit power and the input voltage under the power level may be obtained by calculation; and in the same way, a curve of the linear relationship between the transmit power and the input voltage under each power level may be detected.
A method for controlling a transmit signal of a radio frequency power amplifier in the prior art includes: according to transmit power required by the transmit signal, querying correspondence between transmit power and an input voltage at each power level and obtaining an input voltage and a power level corresponding to the transmit power, adjusting a gain mode to the power level and adjusting an input voltage to the input voltage corresponding to the transmit power, so as to make the transmit signal of the power amplifier meet the requirement.
In the research and implementation process of the prior art, the inventor of the present invention finds that, in the foregoing prior art, a power supply voltage of the power amplifier is constant and unchanged; however, in order to reduce power consumption of the power amplifier, so as to make the power amplifier work at an optimum efficiency point, the power supply voltage of the power amplifier is usually adjusted. After the adjustment, the correspondence between the transmit power and the input voltage under the constant power supply voltage may not serve as precise data for controlling the transmit signal, and it is unable to control the transmit signal to meet the transmitting requirement, according to the correspondence between the transmit power and the input voltage under the constant power supply voltage.